City seeks change to sewer inflow project

The city of Fairfield is awaiting written Department of Natural Resources approval to stray from its plan to combat sewer inflow and infiltration.

Instead of leading a campaign to disconnect footing drains, wastewater superintendent Ellen Myers intends to follow a path laid out by McClure Engineering ? a path that starts with flow monitoring and ends with wider sewer lines.

Fairfield is in the process of fulfilling two state-mandated sewer system improvements ? construction of a sludge tank and installation of a backup generator ? but is out of compliance with the 2009 plan to eliminate sources of inflow and infiltration.

?What has been done is the removal of roof drains, and what remains to be done ? that is potentially problematic ? is the removal of footing drains. That requires a lot of expense and disruption for the homeowner,? Myers said. ?Other communities have done footing drains. Indianola has a really aggressive footing drain program, but it?s extremely unpopular ?

?We?re not 100 percent sure at this point in time that that?s our major problem,? Myers said.

McClure Engineering proposes the collection system instead be evaluated from the perspective of 19 sewersheds. Monday, the Fairfield City Council authorized up to $248,050 for McClure to install 17 flow meters to gather more comprehensive dry and wet weather data.

An additional $22,500 was authorized for compilation of the data and a final report.

McClure will monitor the system for 90 days in the spring and inspect and assign Global Information System coordinates to each manhole. McClure?s findings should complement data Fairfield already has on file from televising the city?s sewer system.

Myers said, ?[We will] get some idea of the volume of water that?s moving through the pipes, see where the bottlenecks are and be able to try to start planning what we?re going to do about it.?

She anticipates the study will identify locations where wider sewer pipes are needed.

?Those larger sewers will do a better job of getting the water to the sewer, as opposed to having it be throttled down someplace and then come out,? Myers said.

Renovating the collection system won?t, however, be enough to solve all of Fairfield?s sewer problems. The wastewater treatment facility is in need of modernization as well ? equipment that can handle increased flow.

?The headwork structure that we have now is really primitive. It does not do a good job of cleaning the water the way it?s suppose to, so all of the downstream processes work properly,? Myers said. ?We have a couple of structures that are well beyond their useful life: the grit removal facility, the parshall flume and the primary clarifier.?

Those will need to be replaced.

The DNR has set 2019 as the deadline for eliminating sanitary sewer overflows, but Fairfield City Administrator Jeff Clawson has imposed an earlier deadline ? 2017 ? for achieving that goal.

?Right now ? there are so many problems with the sewer system ? it?s in such deteriorated shape ? that you?re standing there looking at a mountain, trying to figure out where should I go dig,? Myers said. ?We really need this assessment [from McClure] to evaluate where best to spend that money because we can fix any number of things and have no impact.?

Councilman Daryn Hamilton commended Clawson and Myers Monday on their decision to move in this direction.

?We still have a very major problem with water infiltrating the system, and with monitoring like this, both wet and dry time periods, I think we?re going to be able to determine where we need to target our money more effectively,? Hamilton said. ?This is a very positive step.?